new cam, Dyno graph. Experts please help
Thread Starter
Instructor
Joined: Jan 2007
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From: South Shore MA
new cam, Dyno graph. Experts please help
Installed my new cam here's the dismal results... additional info can be found at this thread http://forums.corvetteforum.com/c5-t...nd-dyno-s.html.
Safety Car
Joined: May 2004
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From: Simpsonville SC
Something isnt right. I had a stock 99 coupe MN6 with Borla Exhaust and I made 345 rwhp. The air/fuel looks ok. Not sure if something else is failing. Very odd, hopefully some one will chime in and help.
Bryan
Bryan
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Joined: Jan 2007
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From: Dyer, IN
Unless I'm missing something, you have an unresolved issue with the knock sensor(s). As long as the knock sensor is sensing a false knock, the PCM will pull timing. I had this happen to me as well. If the intake has been off, you may have pinched the harness, or may have a bad sensor. You can have the tuner turn down the sensitivity to see if that helps as well.
Thread Starter
Instructor
Joined: Jan 2007
Posts: 149
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From: South Shore MA
The knock sensors are working properly as far as I know. The tuner was only able to get 21* of timing without KS intervention. He was using HP tuner and was showing me anytime the KS was active, on this graph it did not activate. Thanks for your idea! He thinks its suspicious that he can only get 21* he said he would like to see around 27*. He suggested plugged cats? Any ideas?
Last edited by trk982003; May 18, 2010 at 06:29 PM.
Tech Contributor
Joined: Jan 2007
Posts: 19,421
Likes: 1,146
From: Dyer, IN
The knock sensors are working properly as far as I know. The tuner was only able to get 21* of timing without KS intervention. He was using HP tuner and was showing me anytime the KS was active, on this graph it did not activate. Thanks for your idea! He thinks its suspicious that he can only get 21* he said he would like to see around 27*. He suggested plugged cats? Any ideas?
Thread Starter
Instructor
Joined: Jan 2007
Posts: 149
Likes: 2
From: South Shore MA
I see what your saying, hmmm. To answer your question the intake has not been off. We were thinking that too much back pressure is whats causing the KS to react. Its has 4 cats, and they're aftermarket rebuilds. (still $1200 pipe at the time) and maybe leaning out the mixture? The dyno graph plateaus hard around 5k rpm. I'll certainly suggst the KS sensitivity to him, but i wanna safe tune. Detonation makes me cringe and never wanna hear it. Thanks for your input it makes sence to me.
